Just seen this thread shmmeee, so sorry I haven't wished you well before .
I've been married 24 years and for 22 would say been very happy but with every marriage it does go through some massive lows. At the moment I have no idea what person will walk through the door in the evening, she's so up and down I haven't a scooby do what's she's going to be like. New job that takes all her time up and it's totally consumed her.
Being 54 soon I'm considering if it may be time to get out and take a breather myself, kids have all but left home and having my own space again is very appealing.
I'm in the second year of an engineering degree as I had to re-train like you, but mine was due to an accident sometime ago, but I can't do manual work anymore. I need to hold on Uni till I pass then make a final decision.
I can only advise to put all your energy into minimising the effect this will have on your kids. I truely believe that all they want is for you to be happy, so if that means you being away from them some days then they will adjust and really look forward to seeing you, your relationship could even get stronger.
Be strong with your ex, don't give her any ground, yes it will be tough but you have to look after your interests not just for your sake but your kids futures as well.
We are all distant mates on here, so use us as there are some thoughtful posters on here, as you will get impartial advice you won't get from friends who know both of you well, even your solicitor won't give you impartial advice, so use us when you feel you need feedback.
Most importantly as well keep up with Uni as that's for you and your kids futures , and safeguard the most important relationship in all of this.